[llvm] r198222 - Revert r198208 and reapply:

Eric Christopher echristo at gmail.com
Mon Dec 30 09:22:27 PST 2013


Author: echristo
Date: Mon Dec 30 11:22:27 2013
New Revision: 198222

URL: http://llvm.org/viewvc/llvm-project?rev=198222&view=rev
Log:
Revert r198208 and reapply:

      r198196: Use a pointer to keep track of the skeleton unit for each normal unit and construct it up front.
      r198199: Reapply r198196 with a fix to zero initialize the skeleton pointer.
      r198202: Fix aranges and split dwarf by ensuring that the symbol and relocation back to the compile unit from the aranges section is to the skeleton unit and not the one in the dwo.

with a fix to use integer 0 for DW_AT_low_pc since the relocation to the text section symbol was causing issues with COFF. Accordingly remove addLocalLabelAddress and machinery since we're not currently using it.

Modified:
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
    llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h
    llvm/trunk/test/DebugInfo/X86/arange.ll
    llvm/trunk/test/DebugInfo/X86/fission-cu.ll
    llvm/trunk/test/DebugInfo/X86/stmt-list-multiple-compile-units.ll

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp?rev=198222&r1=198221&r2=198222&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.cpp Mon Dec 30 11:22:27 2013
@@ -773,12 +773,6 @@ DwarfCompileUnit *DwarfDebug::constructD
                  DIUnit.getLanguage());
   NewCU->addString(Die, dwarf::DW_AT_name, FN);
 
-  // 2.17.1 requires that we use DW_AT_low_pc for a single entry point
-  // into an entity. We're using 0 (or a NULL label) for this. For
-  // split dwarf it's in the skeleton CU so omit it here.
-  if (!useSplitDwarf())
-    NewCU->addLabelAddress(Die, dwarf::DW_AT_low_pc, NULL);
-
   // Define start line table label for each Compile Unit.
   MCSymbol *LineTableStartSym =
       Asm->GetTempSymbol("line_table_start", NewCU->getUniqueID());
@@ -831,11 +825,11 @@ DwarfCompileUnit *DwarfDebug::constructD
   NewCU->initSection(
       useSplitDwarf() ? Asm->getObjFileLowering().getDwarfInfoDWOSection()
                       : Asm->getObjFileLowering().getDwarfInfoSection(),
-      // FIXME: This is subtle (using the info section even when
-      // this CU is in the dwo section) and necessary for the
-      // current arange code - ideally it should iterate
-      // skeleton units, not full units, if it's going to reference skeletons
-      DwarfInfoSectionSym);
+      useSplitDwarf() ? DwarfInfoDWOSectionSym : DwarfInfoSectionSym);
+
+  // If we're splitting the dwarf then construct the skeleton CU now.
+  if (useSplitDwarf())
+    NewCU->setSkeleton(constructSkeletonCU(NewCU));
 
   CUMap.insert(std::make_pair(DIUnit, NewCU));
   CUDieMap.insert(std::make_pair(Die, NewCU));
@@ -1082,7 +1076,9 @@ void DwarfDebug::finalizeModuleInfo() {
     // Add CU specific attributes if we need to add any.
     if (TheU->getUnitDie()->getTag() == dwarf::DW_TAG_compile_unit) {
       // If we're splitting the dwarf out now that we've got the entire
-      // CU then construct a skeleton CU based upon it.
+      // CU then add the dwo id to it.
+      DwarfCompileUnit *SkCU =
+          static_cast<DwarfCompileUnit *>(TheU->getSkeleton());
       if (useSplitDwarf()) {
         // This should be a unique identifier when we want to build .dwp files.
         uint64_t ID = 0;
@@ -1092,19 +1088,21 @@ void DwarfDebug::finalizeModuleInfo() {
         }
         TheU->addUInt(TheU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
                       dwarf::DW_FORM_data8, ID);
-        // Now construct the skeleton CU associated.
-        DwarfCompileUnit *SkCU =
-            constructSkeletonCU(static_cast<DwarfCompileUnit *>(TheU));
         SkCU->addUInt(SkCU->getUnitDie(), dwarf::DW_AT_GNU_dwo_id,
                       dwarf::DW_FORM_data8, ID);
-      } else {
-        // Attribute if we've emitted a range list for the compile unit, this
-        // will get constructed for the skeleton CU separately if we have one.
-        if (DwarfCURanges && TheU->getRanges().size())
-          addSectionLabel(Asm, TheU, TheU->getUnitDie(), dwarf::DW_AT_ranges,
-                          Asm->GetTempSymbol("cu_ranges", TheU->getUniqueID()),
-                          DwarfDebugRangeSectionSym);
       }
+
+      // If we've requested ranges and have them emit a DW_AT_ranges attribute
+      // on the unit that will remain in the .o file, otherwise add a DW_AT_low_pc.
+      // FIXME: Also add a high pc if we can.
+      // FIXME: We should use ranges if we have multiple compile units.
+      DwarfCompileUnit *U = SkCU ? SkCU : static_cast<DwarfCompileUnit *>(TheU);
+      if (DwarfCURanges && TheU->getRanges().size())
+        addSectionLabel(Asm, U, U->getUnitDie(), dwarf::DW_AT_ranges,
+                        Asm->GetTempSymbol("cu_ranges", U->getUniqueID()),
+                        DwarfDebugRangeSectionSym);
+      else
+        U->addUInt(U->getUnitDie(), dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
     }
   }
 
@@ -2007,6 +2005,9 @@ void DwarfDebug::emitSectionLabels() {
   // Dwarf sections base addresses.
   DwarfInfoSectionSym =
       emitSectionSym(Asm, TLOF.getDwarfInfoSection(), "section_info");
+  if (useSplitDwarf())
+    DwarfInfoDWOSectionSym =
+        emitSectionSym(Asm, TLOF.getDwarfInfoDWOSection(), "section_info_dwo");
   DwarfAbbrevSectionSym =
       emitSectionSym(Asm, TLOF.getDwarfAbbrevSection(), "section_abbrev");
   if (useSplitDwarf())
@@ -2872,7 +2873,7 @@ void DwarfDebug::emitDebugARanges() {
     Asm->OutStreamer.AddComment("DWARF Arange version number");
     Asm->EmitInt16(dwarf::DW_ARANGES_VERSION);
     Asm->OutStreamer.AddComment("Offset Into Debug Info Section");
-    Asm->EmitSectionOffset(CU->getLabelBegin(), CU->getSectionSym());
+    Asm->EmitSectionOffset(CU->getLocalLabelBegin(), CU->getLocalSectionSym());
     Asm->OutStreamer.AddComment("Address Size (in bytes)");
     Asm->EmitInt8(PtrSize);
     Asm->OutStreamer.AddComment("Segment Size (in bytes)");
@@ -2997,15 +2998,6 @@ DwarfCompileUnit *DwarfDebug::constructS
   else
     NewCU->addSectionOffset(Die, dwarf::DW_AT_GNU_addr_base, 0);
 
-  // Attribute if we've emitted a range list for the compile unit, this
-  // will get constructed for the skeleton CU separately if we have one.
-  if (DwarfCURanges && CU->getRanges().size())
-    addSectionLabel(Asm, NewCU, Die, dwarf::DW_AT_ranges,
-                    Asm->GetTempSymbol("cu_ranges", CU->getUniqueID()),
-                    DwarfDebugRangeSectionSym);
-  else
-    NewCU->addUInt(Die, dwarf::DW_AT_low_pc, dwarf::DW_FORM_addr, 0);
-
   // DW_AT_stmt_list is a offset of line number information for this
   // compile unit in debug_line section.
   // FIXME: Should handle multiple compile units.

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h?rev=198222&r1=198221&r2=198222&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfDebug.h Mon Dec 30 11:22:27 2013
@@ -429,7 +429,8 @@ class DwarfDebug : public AsmPrinterHand
   MCSymbol *DwarfStrSectionSym, *TextSectionSym, *DwarfDebugRangeSectionSym;
   MCSymbol *DwarfDebugLocSectionSym, *DwarfLineSectionSym, *DwarfAddrSectionSym;
   MCSymbol *FunctionBeginSym, *FunctionEndSym;
-  MCSymbol *DwarfAbbrevDWOSectionSym, *DwarfStrDWOSectionSym;
+  MCSymbol *DwarfInfoDWOSectionSym, *DwarfAbbrevDWOSectionSym;
+  MCSymbol *DwarfStrDWOSectionSym;
   MCSymbol *DwarfGnuPubNamesSectionSym, *DwarfGnuPubTypesSectionSym;
 
   // As an optimization, there is no need to emit an entry in the directory

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp?rev=198222&r1=198221&r2=198222&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.cpp Mon Dec 30 11:22:27 2013
@@ -43,7 +43,7 @@ GenerateDwarfTypeUnits("generate-type-un
 DwarfUnit::DwarfUnit(unsigned UID, DIE *D, DICompileUnit Node, AsmPrinter *A,
                      DwarfDebug *DW, DwarfFile *DWU)
     : UniqueID(UID), Node(Node), UnitDie(D), DebugInfoOffset(0), Asm(A), DD(DW),
-      DU(DWU), IndexTyDie(0), Section(0) {
+      DU(DWU), IndexTyDie(0), Section(0), Skeleton(0) {
   DIEIntegerOne = new (DIEValueAllocator) DIEInteger(1);
 }
 

Modified: llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h?rev=198222&r1=198221&r2=198222&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h (original)
+++ llvm/trunk/lib/CodeGen/AsmPrinter/DwarfUnit.h Mon Dec 30 11:22:27 2013
@@ -146,12 +146,21 @@ protected:
   /// The label for the start of the range sets for the elements of this unit.
   MCSymbol *LabelRange;
 
+  /// Skeleton unit associated with this unit.
+  DwarfUnit *Skeleton;
+
   DwarfUnit(unsigned UID, DIE *D, DICompileUnit CU, AsmPrinter *A,
             DwarfDebug *DW, DwarfFile *DWU);
 
 public:
   virtual ~DwarfUnit();
 
+  /// Set the skeleton unit associated with this unit.
+  void setSkeleton(DwarfUnit *Skel) { Skeleton = Skel; }
+
+  /// Get the skeleton unit associated with this unit.
+  DwarfUnit *getSkeleton() const { return Skeleton; }
+
   /// Pass in the SectionSym even though we could recreate it in every compile
   /// unit (type units will have actually distinct symbols once they're in
   /// comdat sections).
@@ -171,11 +180,27 @@ public:
     return Section;
   }
 
+  /// If there's a skeleton then return the section symbol for the skeleton
+  /// unit, otherwise return the section symbol for this unit.
+  MCSymbol *getLocalSectionSym() const {
+    if (Skeleton)
+      return Skeleton->getSectionSym();
+    return SectionSym;
+  }
+
   MCSymbol *getSectionSym() const {
     assert(Section);
     return SectionSym;
   }
 
+  /// If there's a skeleton then return the begin label for the skeleton unit,
+  /// otherwise return the local label for this unit.
+  MCSymbol *getLocalLabelBegin() const {
+    if (Skeleton)
+      return Skeleton->getLabelBegin();
+    return LabelBegin;
+  }
+
   MCSymbol *getLabelBegin() const {
     assert(Section);
     return LabelBegin;

Modified: llvm/trunk/test/DebugInfo/X86/arange.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/arange.ll?rev=198222&r1=198221&r2=198222&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/arange.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/arange.ll Mon Dec 30 11:22:27 2013
@@ -1,6 +1,7 @@
 ; REQUIRES: object-emission
 
 ; RUN: llc -mtriple=x86_64-linux -O0 -filetype=obj < %s | llvm-dwarfdump -debug-dump=aranges - | FileCheck %s
+; RUN: llc -mtriple=x86_64-linux -O0 -filetype=obj < %s | llvm-readobj --relocations - | FileCheck --check-prefix=OBJ %s
 
 ; extern int i;
 ; template<int *x>
@@ -15,6 +16,10 @@
 ; CHECK-NEXT: [0x
 ; CHECK-NOT: [0x
 
+; Check that we have a relocation back to the debug_info section from the debug_aranges section
+; OBJ: debug_aranges
+; OBJ-NEXT: R_X86_64_32 .debug_info 0x0
+
 %struct.foo = type { i8 }
 
 @f = global %struct.foo zeroinitializer, align 1

Modified: llvm/trunk/test/DebugInfo/X86/fission-cu.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/fission-cu.ll?rev=198222&r1=198221&r2=198222&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/fission-cu.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/fission-cu.ll Mon Dec 30 11:22:27 2013
@@ -25,19 +25,19 @@
 ; CHECK: [1] DW_TAG_compile_unit DW_CHILDREN_no
 ; CHECK: DW_AT_GNU_dwo_name      DW_FORM_strp
 ; CHECK: DW_AT_GNU_addr_base     DW_FORM_sec_offset
-; CHECK: DW_AT_low_pc    DW_FORM_addr
 ; CHECK: DW_AT_stmt_list DW_FORM_sec_offset
 ; CHECK: DW_AT_comp_dir  DW_FORM_strp
 ; CHECK: DW_AT_GNU_dwo_id        DW_FORM_data8
+; CHECK: DW_AT_low_pc    DW_FORM_addr
 
 ; CHECK: .debug_info contents:
 ; CHECK: DW_TAG_compile_unit
 ; CHECK: DW_AT_GNU_dwo_name [DW_FORM_strp] ( .debug_str[0x00000000] = "baz.dwo")
 ; CHECK: DW_AT_GNU_addr_base [DW_FORM_sec_offset]                   (0x00000000)
-; CHECK: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 ; CHECK: DW_AT_stmt_list [DW_FORM_sec_offset]   (0x00000000)
 ; CHECK: DW_AT_comp_dir [DW_FORM_strp]     ( .debug_str[0x00000008] = "/usr/local/google/home/echristo/tmp")
 ; CHECK: DW_AT_GNU_dwo_id [DW_FORM_data8]  (0x0000000000000000)
+; CHECK: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 
 ; CHECK: .debug_str contents:
 ; CHECK: 0x00000000: "baz.dwo"
@@ -111,4 +111,7 @@
 ; OBJ-NEXT: R_X86_64_32 .debug_line
 ; OBJ-NEXT: R_X86_64_32 .debug_str
 ; OBJ-NEXT: }
+; OBJ: .debug_aranges
+; OBJ-NEXT: R_X86_64_32 .debug_info 0x0
+
 !9 = metadata !{i32 1, metadata !"Debug Info Version", i32 1}

Modified: llvm/trunk/test/DebugInfo/X86/stmt-list-multiple-compile-units.ll
URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/DebugInfo/X86/stmt-list-multiple-compile-units.ll?rev=198222&r1=198221&r2=198222&view=diff
==============================================================================
--- llvm/trunk/test/DebugInfo/X86/stmt-list-multiple-compile-units.ll (original)
+++ llvm/trunk/test/DebugInfo/X86/stmt-list-multiple-compile-units.ll Mon Dec 30 11:22:27 2013
@@ -7,12 +7,12 @@
 ; rdar://13067005
 ; CHECK: .debug_info contents:
 ; CHECK: DW_TAG_compile_unit
-; CHECK: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 ; CHECK: DW_AT_stmt_list [DW_FORM_sec_offset]   (0x00000000)
+; CHECK: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 
 ; CHECK: DW_TAG_compile_unit
-; CHECK: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 ; CHECK: DW_AT_stmt_list [DW_FORM_sec_offset]   (0x0000003c)
+; CHECK: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 
 ; CHECK: .debug_line contents:
 ; CHECK-NEXT: Line table prologue:
@@ -25,12 +25,12 @@
 
 ; DWARF3: .debug_info contents:
 ; DWARF3: DW_TAG_compile_unit
-; DWARF3: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 ; DWARF3: DW_AT_stmt_list [DW_FORM_data4]   (0x00000000)
+; DWARF3: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 
 ; DWARF3: DW_TAG_compile_unit
-; DWARF3: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 ; DWARF3: DW_AT_stmt_list [DW_FORM_data4]   (0x0000003c)
+; DWARF3: DW_AT_low_pc [DW_FORM_addr]       (0x0000000000000000)
 
 ; DWARF3: .debug_line contents:
 ; DWARF3-NEXT: Line table prologue:





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